I have spreadsheets filled with material lists for every phase of the build that includes pricing for materials as well as labor, and sources that I use for them.

You have to include the cost of your time and the work, especially on a "scary house" is daunting indeed. 

The client will be solely responsible for capital gains taxes, including depreciation recapture, regardless of the agreement to share proceeds.

Aloha Barbara,We live on Maui, are accredited investors and invest in several syndications including Self Storage. 

We purchased 133.7 acres January 20th of 2024, we then proceeded to subdivide 4 building lots, ( two 10 acre lots,  and two 2 acre lots)  which included costs associated with septic testing,  survey & subdivision, and property maintenence required to market the building lots.

When its included in a lease for real estate then the laws pertaining to residential rental security deposits in your state apply but when its separate you should have more leeway to get some additional deposit to protect you.

Quote from @John Jones: What is exactly included in the Basic subscription of Invelo, which is included with Pro BiggerPockets? 

You must must disclose to the seller everything including that you are selling it to someone else and how much money you are selling it to that end buyer.

Don’t forget to include the cost of the loan servicer. 

Along with the dwelling unit described herein, the Premises include the following: (i) _____ Storage Locker; (ii) _____ Parking space(s) (Identified as _____ and containing _____ parking spaces (also see Section 9 below); (iii) _____ Garage (Identified as _____ and containing _____ parking spaces and _____ transmitters (also see Section 9 below).